Clock



Nov. 16, 1937. R. H. WHITEHEAD 2,099,414

CLOCK Filed Aug. 8, 1934 s Sheets-Sheet 1 IN V EN TOR.

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NOV. 16, 1937. R H WHITEHEAD 2,099,414

CLOCK 3 Sheets-Sheet 2 Filed Aug. 8, 1954 Fig. 4

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Nov. 16, 1937.

R. H. WHITEHEAD CLOCK Filed Aug. 8, 1934 5 Sheets-Sheet 3 Fig. 7.

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Patented Nov. 16, 1937 UNITED STATES PATENT OFFICE Application August 8,

2 Claims.

This invention relates to clocks. It is an object of this invention to provide an escapement clock in which the noise of the escapement will be reduced to a minimum but having such a construction that it can be manufactured inexpensively on a quantity basis and will be emcient and reliable.

In the manufacture of spring clocks, particularly the ordinary type of inexpensive clock such as an alarm clock, there are times, such as in the dead of night, when the tick of the escapement becomes objectionably noticeable. It is an object of this invention to provide a construction adapted particularly for inexpensive clocks which will reduce this noise to a minimum.

The term escapement lever" is used herein to designate the oscillating member which carries the pallet pins. The term fork is used to designate the forked element which engages the pin upon the escapement wheel which may be carried by the escapement lever or by other means as for example by separate lever.

The noise of a clock movement is partly caused by the blow of contact between the teeth of the escapement wheel and the pallets of the escapement lever and this noise is greatly increased by the fact that the plates of the clock which are of metal, serve in the nature of a sounding board to which the vibrations are directly transmitted by the standard clock mechanism heretofore in use.

It is an object of this invention to decrease the force of the blow between the contacting parts so as to reduce the source of the noise to a minimum.

It is a further object to reduce the effect of the blow in producing noise by introducing a cushioning device between the supporting plate and the elements which cause the blow so as to interfere with the transmission of the vibration to the plates.

The invention accordingly comprises the features of construction, combinations of elements, and arrangements of parts, which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the claims.

The invention accordingly comprises an article of manufacture possessing the features, properties, and the relation of elements which will be exemplified in the article hereinafter described and the scope of the application of which will be indicated in the claims.

In the drawings, Figure 1 is a perspective view 1934, Serial No. 738,958

of an escapement of a block embodying this invention.

Figure 2 is an elevation of the escapement wheel thereof,

Figure 3 is a vertical section of the construction shown in Figure 2,

Figure 4 is a perspective view of a modified construction,

Figure 5 is an elevation of the escapement wheel and balance lever of the construction of Figure 4,

Figures 6 is a cross-section of the balance lever of the same,

Figure 7 is a perspective view of another modiflcation,

Figure 8 is an elevation of the balance lever and escapement wheel of the construction of Figure 7,

Figure 9 is a vertical section of the same,

Figure 10 is a plan view of an escapement wheel of a modified form of the structure,

Figure 11 is a central section thereof.

In a clock in which the time is controlled by an escapement, the sources of noise comprise the blow with which the teeth of the escapement wheel strike the pallets on the escapement lever and to a lesser extent, the blow with which the pin on the balance wheel strikes the fork which drives the escapement lever. The noise of these contacts is transmitted through the gears and shafts to the side plates which hold the gear train in place and set those plates in vibration. The reduction in the sound may be obtained by reducing the blow with which the elements contact and by reducing the response thereto of the retaining plates.

In the embodiment of the invention shown in Figure 1, the numeral l0 designates one of the retaining plates of a clock on which there is mounted the balance wheel I l controlled by a hair spring l2. An escapement lever I3 is also pivoted in the plates III as at H, carrying pins or pallets I5 in position to cooperate with an escapement member I6 also mounted in the end plates. This escapement member is driven by and controls the speed of a clock movement which may be otherwise of a conventional design. The escapement lever l 3 has provided at its upper end [8 the usual fork to engage with a balance wheel pin l9 carried by the balance wheel.

The escapement member IS, in this embodiment, (see particularly Figures 2 and 3), is composed of two portions, an outer portion or escapement wheel which may have the general contour of a standard escapement wheel having escapement teeth I'll, and it may be driven by being attached directly to the shaft 2!. Loosely mounted upon the shaft 2| is an auxiliary wheel which is connected to the escapement wheel by means of a spring 23, connected at one end to the wheel 2i] and at the other end to the wheel This wheel 22 has teeth 24, corresponding in position and size to the teeth ll upon the escapement wheel 25], as will be seen more clearly from Figure 2. The teeth 24 of the auxiliary wheel are preferably made shorter than the teeth H on the escapement wheel. A pin 25 fastened to the wheel 20 extends through an opening 26 in wheel 22, there being sufiicient clearance to permit a slight movement between the. wheels. The spring 23 is arranged normally to hold'the teeth it slightly in advance in front of theteeth H as far as the clearance around the pin 25 will permit, so that as each pallet comes down in between the teeth, and the escapement wheel is released by the other pallet, the blow occurs upon the teeth 24 of the auxiliary wheel 22 which yields and thus serves to cushion the blow and reduce the noise. As soon, however, as the pallet pin is lifted outwardly beyond the ends of the teeth 24, the pallets of the escapement lever, riding upon the inclined out ends of the teeth, I1, permit the spring 23 again to move the auxiliary wheel 22 forward relative to the escapement wheel.

With this construction it will be clear that the blow of the escapement is received by a member which is not rigidly connected to the gearing. It will be understood, however, that there may be provided a certain friction between the two wheels 2i) and 22 so that the energy of the blow is absorbed with a corresponding saving in the noise produced and to insulate the blow from the retaining plates.

In the embodiment of the invention shown in Figures 4 to 6, the fork I8 is carried upon an arm 33 which is separate from the escapement lever 36, at least one of these elements being loose upon this shaft 34. In the particular embodiment illustrated, an escapement lever 30 is fixed upon the shaft 34 and has an extension 30a beyond the shaft parallel to the arm 33. The arm 33 is loose upon the shaft 34 and is loosely pivoted to the extension 30a of the escapement lever 36 by a pin 38 fixed to the arm 33 and extending through an opening in the extension 3%. A spring 39 attached to the escapement lever 36 at one end connects to a pin upon the arm 33 to hold the escapement lever 30 and the arm 33 centered with regard to each other. With this construction the pallet pins have a certain amount of lost motion with regard to the fork and this lost motion is spring centered and controlled by friction so that the blow between the escapement wheel and the balance wheel is cushioned before being transmitted to the frame.

In the form of the invention illustrated in Figure 7, the escapement wheel 40 is loosely mounted upon its shaft 4| by a hub 42 having a circumferential groove 43 for carrying the escapement wheel 43. This hub is connected to the escapement wheel by a spring 44 so that the shock of the blow upon the escapement wheel is not directly transmitted to the escapement wheel shaft. In this embodiment the fork is carried by an arm 45 which is fixed upon the shaft 46 and the escapement lever 43 carries pallets 50 which extend through clearance holes 5! in the arm 45. A spring 52 maintains the escapement lever 49 in a central position with regard to the arm 45.

In this embodiment the energy of the blow is cushioned and absorbed by the yielding of the pallet pins and of the escapement wheel and the resilient mounting prevents the direct transmission of the blow to the supporting plates.

In the form of the invention shown in Figures 10 and 11 there is mounted upon the escapement wheel shaft 66 a disk iii. The escapement wheel 62 is mounted loosely upon the shaft 60 adjacent to the diskand a pin 63 upon the escapement wheel extends through an opening 64 in the disk with a certain amount of play to permit a limited motion of the escapement wheel relative to the disk. This motion will be sufficient to absorb the blow but insuificient to allow the escapement wheel to get out of timing with the movement of the time train and the balance wheel. To urge the escapement wheel to its forward position with regard to the disk as far as the limit of motion will permit, there is provided upon the disk a spring 65 adapted to bear against the pin 63.

With this'construction it will be clear that as each tooth of the escapement Wheel strikes a pallet pin the force of the blow will be taken by the escapement wheel which will momentarily remain stationary while the diskmoves on so that the escapement wheel is in effect moved backward relative to the disk. The effect of the blow between the tooth and the pallet is thus reduced by the spring cushion and the energy of the blow is absorbed by the friction between the disk and the escapement wheel. Moreover, it will be observed that while the disk is fast upon the shaft, the escapement wheel itself is loose so that there is no rigid connection between the escapement wheel tooth which receives the blow and the supporting plates so that there is in effect inserted a cushion between the blow and the supporting plates and the latter do not have the same opportunity to resonate as a sounding board, on that account. As soon as the energy of theblow has been absorbed by the relative movement between the escapement wheel and the disk, the spring 65 again moves the escapement wheel forward to its initial position ready to receive the blow of the other pallet pin.

The effect of sound insulation can be still further improved by insulating the movement from the case as for example by the employment of rubber insulation as shown in the patent to Chamberlain 1,957,694.

Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from-the scope thereofQit is intended that all matter contained inthe above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween;

What I claim and desire to secure by Letters Patent is:

= 1. In a. clock in combination, a balance wheel, a shaft, an escapement lever carrying pallet pins, mounted on said shaft, a fork lever adapted to be engaged by the balance wheel for operating said escapement lever and pivoted to the escapement lever distant from the shaft and a resilient connection between said fork lever and said escapement lever.

2. In a clock in combination, an escapement lever carrying pallet pins, an escapement wheel shaft, an escapement wheel loosely mounted on said shaft, a disc fixed upon said shaft of smaller diameter than said escapement wheel carrying an abutment, a pin upon said escapement wheel in the path of said abutment, and a spring holding said pin in contact with said abutment, except when the movement of said escapement wheel imparts a blow to one or the other of the pallet pins, said disc exerting sufiicient friction against said escapement wheel to dampen any oscillation between the escapement wheel and its shaft.

RICHARD H. WHITEHEAD. 

